This site won't be sending you 'spam'. It has no reason to.
What it does do is [if you accept] provide cookies to recognize your interaction with the site, eg. which pages you visited and whether a response may have been placed with a thread you have visited/read.
Totally inoccuous.
You 'may' be the recipient of 'solicited' email, such as notification of a rejected skin submission, or even have opted into the periodical newsletter.
If you have not submitted works here, nor have opted for receipt of the newsletter then there is exactly no reason for Wincustomize to even acknowledge your existence.....'spam' or otherwise.
I'd suggest this 'spam' is actually something entirely different, such as a email virus infection of some kind where its 'header' is being 'altered' to appear to be from a 'trusted' source.
Currently there is one such doing the rounds.